STRUCTURE AND PHYSIOLOGY
A subspecies of S. enterica, Salmonella typhii is motile, Gram-negative, rod-shaped bacteria. The flagella present on this microorganism allow it to evade the host immune system, increasing its virulence.
TRANSMISSION AND DISEASE
The causative agent of typhoid fever, S. typhii is rare in developed countries, though still prevalent in the developing world. Unlike many Salmonella species, this strain’s only known host is humans. It is typically spread via the fecal-oral route, often from unclean food-service practices. There are now many drug-resistant strains of S. typhii, some even multi-drug-resistant.
Due to its increased virulence and drug-resistant capabilities compared to the standard Salmonella strain, S. typhii is used for additional claims testing for disinfectants and sanitizers.
Ashurst JV, Truong J, Woodbury B. Salmonella Typhi. [Updated 2021 Aug 12]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan. Available from: https://www.ncbi.nlm.nih.gov/books/ NBK519002/